The present invention relates to photography and more particularly to the arrangement of barcodes and data encoded therein on photographic elements for use in photofinishing.
Placing data regarding properties of a photographic element in association with the element is a practice well known in the art. This data can be stored in many ways, including two-dimensional barcode symbols optically printed on to the photographic element.
Optical storage and retrieval of data written in a rectangular grid aligned with the length of the medium for scanning by a linear CCD array has been disclosed in U.S. Pat. No. 4,786,792 issued Nov. 22, 1988 to Pierce et al. entitled Transmissively Read Quad Density Optical Data System, and U.S. Pat. No. 4,634,850 issued on Jan. 6, 1987 to Pierce et al. entitled Quad Density Optical Data System. Unfortunately, we have found that the requirement of alignment of the data grid with the medium leads to loss of data as a result of linear defects present in the photographic element. These defects include but are not limited to scratches, digs, processing draglines, coating streakiness, coating waviness, etc.
Use of two-dimensional barcode symbols to store data is well known in the prior art and many such symbologies have been standardized by national and international standards organizations. For example, the Data Matrix symbology, disclosed in U.S. Pat. No. 4,939,354 issued Jul. 3, 1990 to Priddy et al. entitled Dynamically Variable Machine Readable Binary Code and Method for Reading and Producing Thereof, is the subject of the standards ANSI/AIM BC-11-1997 and ISO/IEC 16022:2000. A second such example, the MaxiCode symbology, disclosed in U.S. Pat. No. 4,874,936 issued Oct. 17, 1989 to Chandler et al. entitled Hexagonal, Information Encoding Article, Process and System, is the subject of the standards ANSI/AIM BC-10-1997 and ISO/IEC 16023:2000. A third such example, the Aztec Code symbology, disclosed in U.S. Pat. No. 5,591,956 issued Jan. 7, 1997 to Longacre et al. entitled Two Dimensional Data Encoding Structure and Symbology for Use with Optical Readers, is the subject of the standard ANSI/AIM BC-13-1998. Such two-dimensional symbologies advantageously contain error detection and correction capability. Further, software used to locate, decode, and detect and correct errors in symbols in a digital image file is readily available. For example, software for locating and decoding the Data Matrix and MaxiCode symbology is available as the SwiftDecoder(trademark) software product from Omniplanar Inc., Princeton, N.J. Finally, the required scanning and digitization equipment needed to obtain digital image files from a photographic element is readily available in the photofinishing industry.
Unfortunately, we have found that despite their built-in error detection and correction capabilities, the use of such two-dimensional barcode symbols remains prone to various inefficiencies, errors, and loss of data as a result of linear defects present in the photographic element.
We have also found that redundant encoding of critical data in multiple independent symbols or regions within symbols does not in itself provide adequate protection against such extended linear defects. Such defects can still affect the ability to efficiently and effectively decode multiple symbols or regions within symbols, particularly when arranging these symbols to efficiently utilize the limited area typically available on a photographic element such as a film strip.
Further, when multiple two-dimensional barcode symbols are used, decoding software must also recognize and separately decode information from each symbol. We have found such software is inefficient when symbols are directly juxtaposed, even in the absence of extended linear defects.
There is a need therefore for an improved barcode and data encoding arrangement that minimizes the problems noted above.
The need is met according to the present invention by providing a method of placing a two-dimensional barcode symbol on a photographic element, the barcode symbol comprising collections of modules arranged in a regular array with a plurality of defined orientation directions, the photographic element exhibiting linear defects in a predominant direction and having a maximum width, that includes the step of orienting the barcode symbol so that each defined orientation direction is rotated relative to the predominant direction sufficient so that no single collection of modules aligned in a defined orientation direction is completely obscured by the defect.
A two-dimensional symbol advantageously may be located and oriented arbitrarily relative to specific directions in the storage medium and the image acquisition system. In the present invention, such a symbol, comprising a regular array of modules, written on a photographic element exhibiting linear defects in a predominant direction, is oriented to enhance efficient and effective data recovery from a symbol corrupted by such a linear defect.
Data advantageously may be partitioned into several segments and encoded in several symbols that in turn may be independently placed on the storage medium. In the present invention, such a collection of symbols, written on a photographic element exhibiting linear defects in a predominant direction, is arranged in an array to enhance efficient and effective data recovery by reducing the number of symbols corrupted by a linear defect. Further, each symbol in such an array is independently oriented or offset relative to the predominant linear defect direction to further enhance efficient and effective data recovery.
Data advantageously may be replicated in several symbols that in turn may be independently placed in an array on the storage medium. In the present invention, symbols containing replicate data, written on a photographic element exhibiting linear defects in a predominant direction, are placed in array positions that are offset relative to the predominant direction so that at most one symbol containing a data item is likely to be corrupted by such a linear defect, thereby assuring data integrity.
Finally, multiple symbols may advantageously be placed with additional space between them. In the present invention, the spacing is selected to aid symbol decoding software in the task of separating the symbols, resulting in increased efficiency in retrieving data even in the absence of extended linear defects.